Researchers at the Indian Institute of Technology (IIT) Guwahati have successfully developed an innovative, energy-efficient building material by embedding biochar-based biocomposites into Autoclaved Aerated Concrete (AAC) bricks. This advancement in India’s sustainable construction sector utilizes Phase Change Materials (PCMs) to regulate indoor temperatures naturally. By integrating these materials, the research team has demonstrated a functional prototype capable of reducing indoor air temperatures by approximately 3°C. This thermal regulation translates into a potential 10% to 20% reduction in total energy consumption for cooling, offering a significant development for climate-responsive architecture in tropical regions.

The primary challenge addressed by this research is the extreme thermal gain experienced by buildings in hot and humid climates, where heat penetration through walls and roofs necessitates intensive mechanical air conditioning. While PCMs are effective at absorbing and releasing latent heat to stabilize temperatures, their application in construction has historically been hindered by leakage issues. When PCMs transition from a solid to a liquid state during the day, they often seep out of porous building materials, compromising structural integrity and long-term thermal performance. Furthermore, optimizing the thermal conductivity of these materials is essential to ensure they respond efficiently to external temperature fluctuations.

To resolve these technical hurdles, the IIT Guwahati team utilized biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More as a stabilizing matrix for the PCM, specifically a formulation identified as OM35. The carbon-rich structure of biochar acts as a robust support system, holding the molten PCM through capillary forces and preventing leakage during the phase transition at 35°C. Beyond containment, the biochar serves to improve the overall thermal conductivity of the composite brick. This allows the PCM to more effectively absorb excess heat during peak daylight hours and discharge it during cooler night-time periods, maintaining the mechanical strength and shape of the AAC bricks even under intense thermal stress.

The outcome of this integration is a sustainable construction component that provides superior thermal management compared to conventional masonry. Computer simulations and experimental testing confirmed that the biochar-stabilized PCM bricks effectively dampen the thermal load of a building, reducing the reliance on electricity-heavy cooling systems. Currently, the production cost is estimated between Rs 115 and 130 per unit, with projections for lower costs through industrial scaling. The researchers are now moving toward commercialization and the potential formation of a startup to bring this biochar-enhanced technology to the international green building market.